Make closures optimizable by Crankshaft compiler.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index a815b0474f5c1f49b2a70f9474730a906406a2cf..254a47af7836d5a6332c154ecbd1779a5fd001e6 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -257,6 +257,11 @@ void LUnaryMathOperation::PrintDataTo(StringStream* stream) {
 }
 
 
+void LLoadContextSlot::PrintDataTo(StringStream* stream) {
+  stream->Add("(%d, %d)", context_chain_length(), slot_index());
+}
+
+
 void LCallKeyed::PrintDataTo(StringStream* stream) {
   stream->Add("[ecx] #%d / ", arity());
 }
@@ -1633,6 +1638,11 @@ LInstruction* LChunkBuilder::DoStoreGlobal(HStoreGlobal* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
+  return DefineAsRegister(new LLoadContextSlot);
+}
+
+
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
   ASSERT(instr->representation().IsTagged());
   LOperand* obj = UseRegisterAtStart(instr->object());